US3527123A - Method and apparatus for assembling blades onto a blade support - Google Patents

Description

Sept. 8, 1970 N E. DOVEY 3,327,123

METHOD AND AI PARATUS FOR ASSEMBLING BLADES ONTO A BLADE SUPPORT Filed March 35, 1968 4&274

FIG. 7

NVENTOR.

I \j 36 e4 NORMAN E, DOVEY BY FIG.8 F|G.9

ATTORNEYS United States Patent 3,527,123 METHOD AND APPARATUS FOR ASSEMBLING BLADES ONTO A BLADE SUPPORT Norman Edward Dovey, Pompano Beach, Fla, assignor to Dovey Manufacturing Company, Anderson, Ind., a corporation of Indiana Filed Mar. 25, 1968, Ser. No. 715,653 Int. Cl. B26d 7/26 US. Cl. 76-107 16 Claims ABSTRACT OF THE DISCLOSURE An improved method and apparatus for assembling cutting blades onto the outer surface of a blade support. The method includes: forming an elongated groove on the outer surface of the support, positioning the blade in the groove; and, force fitting into the groove an elongated, resiliently deformable member having a plurality of closely spaced outwardly extending surface portions on opposite longitudinal sides thereof. In the preferred embodiment, the deformable members are of coil springs and two of them are utilized.

The present invention is directed toward the cutting art and, more particularly, to a method and apparatus for assembling a cutting blade or knife onto a knife support.

The invention is especially suited for assembling steel rule knives onto the outer periphery of a rotary knife support of the type adapted to rotate against a rotary anvil so that cardboard sheets passing between the anvil and the knife support will be out according to the arrangement of the knife and it will be described with particular reference thereto; however, it will be appreciated the invention is capable of much broader application and could be utilized for assembling a variety of types of knives or blades onto many different supports used in the cutting art. In addition, the invention may be used in supporting various thin members edgewise into a groove.

In cutting blanks from cardboard sheets the predominately used arrangement is to mount rule knives into the outer surface of a cylindrical knife support mounted on a rotating shaft. The rule knives are generally flat metal strips having one longitudinal edge constituting a cutting edge and the other edge adapted for securing to the surface of the knife support. A rotary anvil is spaced radially from the knife support and is arranged to cooperate with the knives so that as cardboard sheets are passed between the anvil and the support they are blanked or cut in a configuration dictated by the arrangement of the knives. As can be seen, each revolution of the knife support produces an identical series of cuts or blanks. Consequently, this apparatus is especially suited for economical mass production of cut cardboard articles. Additionally, the apparatus is comparatively simple in construction and has a low first cost, as Well as, low maintainence cost.

Because of its many advantages, the above-mentioned apparatus has been widely accepted as the most suitable apparatus for cutting cardboard. The primary disadvantage of the apparatus is the difficulty of assembling the knives onto the support. Prior to the present invention, a variety of types of connecting means and methods have been utilized with varying degrees of success. For example, one commonly used method was to form the knife support with a plurality of segments having mating contours corresponding to the configuration of the blank to be cut. This method was quite expensive and required precision machining and fitting. Additionally, the number of knife configurations available with any one supice port was limited. Another method utilized was to form grooves in the outer surface of the support and connect the knives therein by wedges of deformable material, such as lead. Alteruately, various types of mechanical clamp and threaded fastener arrangements were utilized. Basically, all of the prior knife mounting arrangements made the job of mounting and removing the knives relatively diflicult and time consuming.

The present invention provides a highly simplified method and apparatus which permits the knives to be mounted and removed simply and in a minimum of time. The subject arrangement maintains the knives rigidly affixed to the support without the use of any threaded or mechanical clamp type fasteners.

In accordance with a primary aspect of the present invention an improved method is provided for assembling onto the outer surface of a blade support an elongated, fiat cutting blade having first and second generally parallel, opposed side walls joined by a longitudinally extending cutting edge. The method comprises the steps of (a) Forming, on the outer surface of the blade sup port, an elongated groove having first and second opposed, generally parallel side walls spaced apart a distance substantially greater than the thickness of the blade and joined by a bottom wall;

(b) Positioning the blade in the groove longitudinally thereof with its cutting edge extending outwardly of the outer surface of the blade support and the first side wall of the blade in engagement with the first side wall of the groove whereby the resulting longitudinal open space in the groove has a width a equal to the width of the groove less the thickness of the blade;

(c) Providing at least a first elongated resiliently deformable member having a plurality of closely spaced outwardly extending surface portions on opposite longitudinal sides thereof, with the transverse distance between the surface portions on opposite sides of the member being slightly greater than a; and

(d) Forcing the member into the open space of the groove to extend longitudinally thereof with the outwardly extending surface portions on one longitudinal side in engagement with the second side wall of the blade and the portions on the other longitudinal side in engagement with the second side wall of the groove, whereby forces generated by the resiliency of the member act through the surface portions and clamp the blade in the groove.

In accordance with another aspect of the present invention apparatus is provided which includes a blade support having an outer surface with an elongated blade receiving groove formed thereon. The groove is defined by first and second generally parallel side walls spaced a given distance apart and a bottom wall extending between the side walls. An elongated blade having outwardly facing, generally parallel first and second side walls joined by a longitudinally extending cutting edge is positioned in the groove longitudinally thereof with the cutting edge extending outwardly of the groove and the first side wall of the blade in engagement with the first side wall of the groove. The blade is firmly maintained in the groove by at least one elongated, resiliently deformable member having a plurality of closely spaced outwardly extending surface portions on opposite longitudinal sides thereof. The normal transverse distance between the surface portions on opposite sides of the member is slightly greater than the distance between the second side wall of the blade and the second side wall of the groove, and the member is force fitted longitudinally in the groove with the outwardly extending surface portions on one longitudinal side being in engagement with the second side wall of the blade and the outwardly extending surface portions on the outer longitudinal side being in engagement with the second side wall of the groove.

Accordingly, a primary object of the present invention is the provision of a method and apparatus which permits blades to be attached to blade supports in an extremely simple manner.

Another object of the present invention is the provision of a method and apparatus which allows blades to be connected to blade supports without the use of rivets, threaded fasteners, or other types of mechanical connectors.

A still further object of the present invention is the provision of a method and apparatus which is especially suited for connecting rule knives to the outer cylindrical surface of rotary knife supports.

A still further object of the invention is the provision of a method and apparatus for connecting a blade to a blade support in a manner which permits the blade to be quickly removed from the support without the. use of tools.

These and other objects and advantages of the invention will become apparent from the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is an end view, somewhat diagrammatic of a rotary cutter of the type used for cutting and blanking cardboard sheets;

FIG. 2 is a cross-sectional view taken on line 2-4 of FIG. 1 and showing the preferred embodiment of the present invention;

FIG. 3 is an end view of one of the connecting members utilized in the FIG. 2 embodiment;

FIG. 4 is a view taken on line 4-4 of FIG. 2;

FIG. 5 is a view taken on line 5-5 of FIG. 2;

FIG. 6 is a pictorial view showing the FIG. 2 embodiment in the process of being assembled or disassembled; and

FIGS. 7, 8 and 9 are, respectively, second, third and fourth embodiments of the subject invention.

Referring specifically to the drawings wherein the showings are for the purpose of illustrating preferred embodiments of the invention only and not for the purpose of limiting same, FIG. 1 shows a side elevation, somewhat diagrammatic, of a rotary knife assembly A of the type utilized for blanking cardboard sheets and, with which, the subject invention is especially suited for use. As shown, the rotary knife assembly A includes a cylindrical blade support member 10 which is mounted for driven rotation on a rotatably driven shaft 12. Knives 14 are mounted on the outer surface of cylindrical member 10 and are arranged to cooperate with a rotatable anvil member '16 which is radially spaced from member 10. As shown, the anvil 16 comprises a cylindrical member 18 rotatably mounted on shaft 20. The outer anvil surface is preferably formed by a heavy layer 22 of some resilient material such as rubber. As is apparent, with the members arranged as described, a sheet of cardboard 24 fed between the support member 10 and the anvil 16 will be cut or blanked in a configuration determined by the layout of knives 14.

The above-described arrangement for the rotary cutting unit A is, so far as described, conventional and of the type predominately used for cutting and blanking cardboard. As previously mentioned, one of the primary problems of this type of cutter has been the difficulty of providing suitable means for releasably connecting the knives to the outer surface of the knife support member 10. The present invention provides a highly simplified method for connecting the blades to the support member.

As shown in FIG. 2, the knife 14 comprises an elongated, relatively fiat blade having outwardly facing opposed side walls 24 and 26 which are joined along one edge by a cutting edge 28. The knife 14 is positioned in a longitudinally extending groove 30 defined by a pair of generally parallel side walls 32 and 34 joined by a lower wall 36. In the particular embodiment under consideration, groove 30 is machined in an intermediate knife support member 38 which is releasably connected to cylindrical member 10 by a plurality of machine screws 40; however, as will become apparent, groove 30 could be formed directly in the outer surface of member 10 or, alternately, defined by plate or angle members connected to the surface of member 10. As shown, the blade 14' is positioned longitudinally of the groove 30 with side wall 24 in engagement with side wall 32 of the groove.

Of particular importance to the present invention is the means utilized to maintain the blade 14 releasably clamped in position in the groove. These means comprise an elongated resiliently deformable member having a plurality of closely spaced, outwardly extending surface portions on opposite longitudinal sides thereof. The member is sized so that the transverse distance between opposite outwardly extending surface portions is slightly greater than the distance between blank surface 26 and groove sidewall 34, which distance is denoted by the letter a in FIG. 2. The member is then progressively forced fitted into the groove 30 so as to extend longitudinally thereof. This causes the outwardly extending surface portions to be forced inwardly until they are spaced a transverse distance substantially equal to the distance a. The resilient nature of the member produces forces which act outwardly through the small individual area of the surface portions to produce a clamping force on the blade.

In the preferred embodiment, the member comprises a spring and the outwardly directed surface portions are thus defined by the outer, diametrically opposed, surfaces of each convolution of the spring. When the spring is force fitted in the groove the outer surface portions of each convolution engage the sidewall 34 of the groove and the sidewall 26 of the blade along a short narrow band approximately of the nature as shown by the shaded areas 50 of FIG. 5. The multiplicity of small closely spaced surface areas 50 produce a relatively high total clamping force on the blade and make it nearly impossible to withdraw the blade with the spring member in position. The spring member, however, can be relatively easily removed by progressively pulling it from the groove in the manner shown in FIG. 6.

Preferably, the spring is inserted into the groove by successively driving in a limited number of convolutions i.e. a short section of spring is first driven in and, thereafter the remaining longitudinal length of the spring is driven in a short section at a time. A variety of types of tools could be utilized for inserting the springs; however, preferably, the tool should be arranged to prevent permanent deformation of the spring while assuring proper locating. A tool suitable for this purpose is shown in FIG. 8. As shown, the tool includes a downwardly extending portion 82 which is sized for easy insertion in the groove 30. The lower end 84 of the tool is shaped to conform to the outer surface of the spring. Additionally, a stop 86 is provided to limit the extent to which the tool can be inserted. Consequently, the spring is always positioned at the same depth in the groove and cannot be permanently deformed irrespective of the amount of force applied to the tool.

As can be seen from the above, the actual force which must be applied at any one time to insert the spring is relatively small; however, the force which must be applied to the blade for removal with the spring in position is extremely high. Additionally, when the spring and blade are sized so as to engage opposite end walls of the groove the inclined nature of the surface areas 50 cause the blade and spring to want to move longitudinally in the groove when an attempt is made to pull the blade from the groove. This of course cannot happen when there is an end wall of the groove in engagement with the spring and blade and, accordingly, the blade is locked even more firmly into position.

Referring again to the preferred embodiment of FIG. 2 it is seen that two springs 44 and 46 are utilized. The springs are preferably of the same size and, as shown in FIG. 3, have a normal diameter b which is slightly larger than distance a. The use of two springs in a manner shown in FIG. 2 is preferred because the blade is thus engaged at two points transverse of its width and it is given greater stability against transverse tilting in the groove. Additionally, as shown in FIGS. 2 and 5, springs 44 and 46 are preferably of the same hand, that is for example, both of the springs are coiled clockwise or, both coiled counterclockwise. This prevents the springs from entering into engagement with one another and shifting the points at whichthey engage the blade. This feature can best be seen in FIG. 4 which shows that the coils of the upper and lower springs cross one another in a diagonal relationship.

When inserting the second spring 46, a tool similar to previously described tool 80 is preferably used. The position of the stop 86 is different however so that the second spring cannot be driven into the first spring. Additionally, it is believed to be more satisfactory if the springs do not engage one another i.e. the lower surface upper spring should be slightly spaced from the top surface of the lower spring.

Although it is preferred to use two springs of the type and in the manner shown in FIG. 2, it is of course understood that other types of springs having less tightly wound convolutions or other types of elongated resilient members having somewhat similarly arranged, outwardly extending portions could be used.

FIG. 7 shows a second modification of the invention which is similar in all respects to the modification shown and described in FIG. 2, except that the blade 60 has a tab portion 62 which is bent at right angles to the main blade portion and engages the bottom Wall 36 of the groove. The tab portion 62 can be continuous along the blade or comprise a plurality of individual tab sections of any desired longitudinal length. The tab portion assists in the original positioning of the blade in the groove and, further, assists in preventing the blade from being tilted transversely in the groove.

Although less desirable, it is possible to use only one spring member for clamping the blade in the groove. Referring specifically to FIGS. 8 and 9, two modifications of the invention wherein only one spring is used are shown. In FIG. 8, one spring is positioned along the bottom of the groove and in engagement with the sidewall of the blade and the sidewall of the groove. This spring is sufficient to prevent the blade from being pulled outwardly of the groove but, does not function as well as the FIG. 2 embodiment for preventing the blade from being twisted in a clockwise direction as viewed in FIG. 8.

The FIG. 9 embodiment also uses only one spring; however, in this embodiment a longitudinally extending, generally rectangular member 64 is positioned in the bottom of the groove and, preferably, closely engages both the blade and the side wall of the groove. This member, in combination with a clamping spring, prevents the blade from being rotated in a clockwise direction.

The invention has been described in great detail sufficient to enable one of ordinary skill in the art to make and use the same. Obviously, modifications and alterations of the preferred embodiments will occur to others upon a reading and understanding of the specification and it is my intention to include all such modifications and alterations as part of my invention insofar as they come within the scope of the appended claims.

Having thus described my invention, I claim:

1. An improved method of assembling onto the outer surface of a blade support, an elongated, flat cutting blade having a thickness defined by first and second opposed, generally parallel sidewalls joined by a longitudinally extending cutting edge, said method comprising the steps of (a) forming, on the outer surface of said blade support, an elongated groove having first and second opposed sidewalls spaced apart a distance substantially greater than the thickness of said blade and joined by a bottom wall;

(b) positioning said blade in said groove longitudinally thereof with its cutting edge extending outwardly of said outer surface of said blade support and one of said sidewalls of said blade in engagement with the first sidewall of said groove whereby the resulting longitudinal open space in said groove has a width a substantially equal to the width of said groove less the thickness of said blade;

(0) providing at least a first elongated resilient deformable member having a plurality of closely spaced outwardly extending surface portions on opposite longitudinal sides thereof, the transverse distance between said surface portions on opposite sides of said member being slightly greater than a; and

(d) forcing said member into the open space of said groove to extend longitudinally thereof with the outwardly extending surface portions on one longitudinal side in engagement with the second sidewall of said blade and the portions on the other longitudinal side in engagement with the second sidewall of said groove, whereby forces generated by the resiliency of said member act through said surface portions and clamp said blade in said groove.

2. The method as defined in claim 1 including the steps of providing a second elongated, resilient deformable member formed similarly with said first member and forcing said second member into said open space to rest upon said first member and have its outwardly extending surface portions in clamping engagement between the second sidewall of said blade and the second sidewall of said groove.

3. The method as defined in claim 1 wherein said first member provided comprises a coil spring.

4. Apparatus comprising in combination: a blade sup port having an outer surface; means forming an elongated blade groove on said outer surface, said groove defined by first and second generally parallel sidewalls spaced a given distance apart and a bottom wall extending between said sidewalls; an elongated blade having outwardly facing, generally parallel first and second sidewalls joined by a longitudinally extending cutting edge, the distance between said sidewalls of said blade being substantially less than the distance between the sidewalls of said groove; said blade being positioned in said groove longitudinally thereof with the cutting edge extending outwardly of said groove and the first sidewall of said blade in engagement with the first sidewall of said groove; and, at least one elongated, resiliently deformable member having a plurality of closely spaced outwardly extending surface portions on opposite longitudinal sides thereof, the normal transverse distance between the surface portion on opposite sides being slightly greater than the distance between said second sidewall of said blade and the second sidewall of said groove, said member being force fitted longitudinally in said groove with the outwardly extending surface portions on one longitudinal side being in engagement with the second sidewall of said blade and the outwardly extending surface portions on the other longitudinal side being in engagement with the second sidewall of said groove.

*5. The apparatus as defined in claim 4 wherein said first elongated member comprises a coil spring.

'6. The apparatus as defined in claim 4 including a second elongated resilient deformable member formed similarly to said first member and force fitted in said groove superjacent said first member.

7. The apparatus as defined in claim 6 wherein said first and second members each comprise coil springs.

8. The apparatus as defined in claim 7 wherein said coil springs are wound in the same directions.

9. The apparatus as defined in claim 6 wherein said first and second members are slightly spaced from one another throughout their length.

10. A method of securing a fiat elongated member having side surfaces edgewise into a groove having sidewalls, said member having a thickness substantially less than said groove, said method comprising the steps of:

(a) placing said member edgewise into said groove to leave an elongated space between at least one side surface of said member and one sidewall of said groove;

(b) providing an elongated resiliently deformable member having a plurality of closely spaced outwardly extending portions on opposite longitudinal sides thereof and having an undeformed width to provide an interference fit between said one surface and said one sidewall; and,

(c) forcing said elongated deformable member progressively into said groove and between said one surface and one sidewall whereby said deformable member is deformed and grips at said extending portions both said one side surface and said one sidewall.

11. A method as defined in claim 10 including the additional steps of:

((1) providing a second elongated resiliently deformable member having a plurality of closely spaced outwardly extending portions on opposite longitudinal sides thereof and having an undeformed width substantially the same as said first mentioned deformable member; and,

(e) forcing said elongated deformable member progressively into said groove and over said first-mentioned deformable member.

112. A method as defined in claim 11 wherein said deformable members are each coil springs.

13'. A method as defined in claim 12 wherein said coil springs have the same spiralled convol-utions.

14. In a cutting device including a thin knife with a thickness defined by side surfaces and a cutting edge, a knife support having a knife supporting groove, and means for holding said knife in said groove, the improvement comprising: said groove having a width greater than the thickness of said knife, and a coil spring-like member force fitted into said groove along one of said side surfaces, said spring having an undeformed diameter to provide an interference fit with one of said side surfaces and said groove.

15. The improvement as defined in claim 14 including a second coil spring-like member overlying said first member and having a forced fit between said one side surface.

16. The improvement as defined in claim 15 wherein said coil spring-like members have the same spiralled convolutions.

References Cited UNITED STATES PATENTS 1,398,474 11/1921 Strawn 83348 X 3,041,752 7/ 1962 Evans 2'87-126 X 3,196,724 7/1965 Frank 83-583 X 3,277,756 10/ 1966 Des Jardins et a1. 83-698 X FOREIGN PATENTS 1,07 3,147 6/ 1967' Great Britain. 687,691 2/1953 Great Britain.

WILLIAM S. LAWSON, Primary Examiner US. Cl. X.R. 83-698; 287-126

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